process startup: Always call Init[Auxiliary]Process() before BaseInit().

For EXEC_BACKEND InitProcess()/InitAuxiliaryProcess() needs to have been
called well before we call BaseInit(), as SubPostmasterMain() needs LWLocks to
work. Having the order of initialization differ between platforms makes it
unnecessarily hard to understand the system and to add initialization points
for new subsystems without a lot of duplication.

To be able to change the order, BaseInit() cannot trigger
CreateSharedMemoryAndSemaphores() anymore - obviously that needs to have
happened before we can call InitProcess(). It seems cleaner to create shared
memory explicitly in single user/bootstrap mode anyway.

After this change the separation of bufmgr initialization into
InitBufferPoolAccess() / InitBufferPoolBackend() is not meaningful anymore so
the latter is removed.

Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de

1 files changed, 5 insertions, 3 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 530caa520b8..58b5960e27d 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -4050,10 +4050,9 @@ PostgresMain(int argc, char *argv[],
 
 		/* Initialize MaxBackends (if under postmaster, was done already) */
 		InitializeMaxBackends();
-	}
 
-	/* Early initialization */
-	BaseInit();
+		CreateSharedMemoryAndSemaphores();
+	}
 
 	/*
 	 * Create a per-backend PGPROC struct in shared memory, except in the
@@ -4068,6 +4067,9 @@ PostgresMain(int argc, char *argv[],
 	InitProcess();
 #endif
 
+	/* Early initialization */
+	BaseInit();
+
 	/* We need to allow SIGINT, etc during the initial transaction */
 	PG_SETMASK(&UnBlockSig);